ABSTRACT
The crucial consideration in any study of second language acquisition is an understanding of the nature of learner systems and how those learner systems come to be. Negotiation of the sort that takes place in conversation is a means to focus a learner's attention on just those areas of language that do not match those of the target language. This chapter discusses two aspects of the picture: comprehension and output. Most models of second language acquisition assume comprehension as a major component. An area that has received attention in recent years is input processing, which has to do with presentation and timing of input in a pedagogical framework. The notion of hypothesis testing has been central to research in second language acquisition for a number of years. Another piece of evidence for the fact that learners test hypotheses through production is the very simple fact of self-correction.
